Exercise pulmonary hypertension by the mPAP/CO slope in primary mitral regurgitation.

AIMS: Exercise-induced pulmonary hypertension (PH), defined by a mean pulmonary arterial pressure over cardiac output (mPAP/CO) slope >3 mmHg/L/min, has important diagnostic and prognostic implications. The aim of this study is to investigate the value of the mPAP/CO slope in patients with more than moderate primary mitral regurgitation (MR) with preserved ejection fraction and no or discordant symptoms. METHODS AND RESULTS: A total of 128 consecutive patients were evaluated with exercise echocardiography and cardiopulmonary testing. Clinical outcome was defined as the composite of mitral valve intervention, new-onset atrial fibrillation, cardiovascular hospitalization, and all-cause mortality. The mean age was 63 years, 61% were male, and the mean LVEF was 66 ± 6%. The mPAP/CO slope correlated with peak VO2 (r = -0.52, P < 0.001), while the peak systolic pulmonary artery pressure (sPAP) did not (r = -0.06, P = 0.584). Forty-six per cent (n = 59) had peak exercise sPAP ≥60 mmHg, and 37% (n = 47) had mPAP/CO slope >3 mmHg/L/min. Event-free survival was 55% at 1 year and 46% at 2 years, with reduced survival in patients with mPAP/CO slope >3 mmHg/L/min (hazard ratio, 4.9; 95% confidence interval, 2.9-8.2; P < 0.001). In 53 cases (41%), mPAP/CO slope and peak sPAP were discordant: patients with slope >3 mmHg/L/mmHg and sPAP <60 mmHg (n = 21) had worse outcome vs. peak sPAP ≥60 mmHg and normal slope (n = 32, log-rank P = 0.003). The mPAP/CO slope improved predictive models for outcome, incremental to resting and exercise sPAP, and peak VO2. CONCLUSION: Exercise PH defined by the mPAP/CO slope >3 mmHg/L/min is associated with decreased exercise capacity and a higher risk of adverse events in significant primary MR and no or discordant symptoms. The slope provides a greater prognostic value than single sPAP measures and peak VO2.

Determinants of myocardial work indices in women.

OBJECTIVE: By incorporating myocardial deformation and afterload, novel echocardiographic myocardial work indices appear to be advantageous compared to load-dependent left ventricular (LV) deformation analyses. As such, these indices may provide a more accurate and, above all, load-independent estimation of LV function in patients with chronically increased afterload. To date however, data on the relation of these indices to clinical and conventional echocardiographic parameters are scarce. PURPOSE: Our aim was to evaluate the relationship between myocardial work indices and age, body mass index (BMI), NTproBNP, the clinical history of arterial hypertension and diastolic dysfunction as well as selected conventional echocardiographic parameters in women. METHODS: We analyzed echocardiographic data of women included in the Berlin Female Risk Evaluation (BEFRI) trial. Global Work Index (GWI), Global Constructive Work (GCW), Global Wasted Work (GWW) and Global Work Efficiency (GWE) were calculated using commercially available software based on noninvasive pressure-strain loops. The impact of selected clinical and echocardiographic characteristics on myocardial work parameters was investigated by uni- and multivariate regression analyses. RESULTS: A total of 224 women were included in the final analysis. 155 of them were normotensive and 69 had a history of arterial hypertension. Diastolic dysfunction was more prevalent in subjects with arterial hypertension. Study participants with arterial hypertension showed higher GWI and GCW whereas GWW and GWE did not significantly differ between groups. GCW and GWW were lower and GWE higher in the presence of normal diastolic function. In multivariate regression analyses, arterial hypertension, LV GLS, and interventricular septal thickness were significantly associated with GWI. GCW showed significant associations with the clinical history of arterial hypertension, LV GLS, age and IVRT. Similarly, LV GLS, IVRT and mitral inflow E wave deceleration time were identified to be significant determinants of GWW and GWE. CONCLUSION: Our data confirm that, in a randomly selected sample of the general urban female population, myocardial work parameters are predominantly determined by LV GLS. In addition, the presence of arterial hypertension was identified to be a significant determinant of GWI and GCW, but not for GWW and GWE. Finally, a prolonged LV relaxation time was significantly associated with GWW and GWE, suggesting more wasted myocardial work and lower GWE values with increasing LV relaxation time.

Prevalence and Predisposing Factors of Non-infectious Cardiac Implantable Electronic Device Lead Masses as Incidental Finding During Transoesophageal Echocardiography: A Retrospective Cohort Study.

Objectives: In this study, we assessed the prevalence and predisposing factors of non-infectious CIED lead masses as incidental finding during transoesophageal echocardiography (TOE). Methods: In a retrospective single centre study, we analysed TOE examinations performed for indications other than infectious endocarditis in 141 patients with CIED. Patients with non-suspicious leads and those with incidental non-infectious lead masses were compared with respect to clinical characteristics, anticoagulation, indication for TOE, and CIED lead characteristics. The odds ratios for non-infectious CIED lead masses were calculated. Results: Non-infectious CIED lead masses were detected in 39 (27.6%) of the 141 patients. They were more often identified on ICD and CRT-D leads compared to pacemaker and CRT-P leads [OR 2.77 (95% CI 1.29-5.95), p = 0.008]. The lifespan of the CIEDs from the first implantation to the index TOE did not differ between both groups. Incidental CIED lead masses were more prevalent in patients who received their device for primary prevention of sudden cardiac death (43.2%) and for resynchronisation (63.6%) but were less prevalent in patients with oral anticoagulation [OR.33 (95% CI.003-1.003), p = 0.048]. Conclusion: Incidental non-infectious CIED lead masses were frequently found in TOE, with highest prevalence in ICD and CRT-D devices implanted for patients with dilated cardiomyopathy. Patients with therapeutic anticoagulation had significantly lower prevalence of CIED lead masses than those without.

Automated quantification of mitral valve tenting volume in functional mitral regurgitation by three-dimensional echocardiography.

BACKGROUND: Tenting of the mitral leaflets is a major pathophysiological factor contributing to functional mitral regurgitation (FMR). A novel software tool allows automated quantification of the tenting volume (TnV) by 3D transesophageal echocardiography (TEE). The aims of this study are to investigate the correlations of biometric patient characteristics with the TnV and whether a threshold value for the diagnosis of a moderate or severe FMR can be calculated for the TnV. METHODS: This explorative and hypothesis-generating study analyzed the TnV of the mitral valve obtained by clinically indicated TEE. The mid-systolic, threefold calculated and averaged TnV from 80 patients with no or mild FMR and 27 patients with moderate or severe FMR was determined using the TomTec 4D MV Assessment tool. RESULTS: The TnV correlated significantly with the body size (r = 0.341), the weight (r = 0.272), and the body surface area (r = 0.320). After the adjustment to the body size, a threshold value of 1.25 cm3 /m was determined for the TnV by using a receiver-operating characteristic curve. This value distinguished moderate to severe from none to mild FMR with a sensitivity of 85% and a specificity of 71%. The intra-observer variability and inter-observer variability were determined to be 0.96 and 0.85, respectively. CONCLUSIONS: Automated assessment of TnV has the potential to support the diagnostic evaluation of FMR. Further studies are needed to validate this result, detect additional factors influencing the size of the TnV, and determine further thresholds for any degree of FMR.

Machine learning of the spatio-temporal characteristics of echocardiographic deformation curves for infarct classification.

The aim of this study was to analyze the whole temporal profiles of the segmental deformation curves of the left ventricle (LV) and describe their interrelations to obtain more detailed information concerning global LV function in order to be able to identify abnormal changes in LV mechanics. The temporal characteristics of the segmental LV deformation curves were compactly described using an efficient decomposition into major patterns of variation through a statistical method, called Principal Component Analysis (PCA). In order to describe the spatial relations between the segmental traces, the PCA-derived temporal features of all LV segments were concatenated. The obtained set of features was then used to build an automatic classification system. The proposed methodology was applied to a group of 60 MRI-delayed enhancement confirmed infarct patients and 60 controls in order to detect myocardial infarction. An average classification accuracy of 87% with corresponding sensitivity and specificity rates of 89% and 85%, respectively was obtained by the proposed methodology applied on the strain rate curves. This classification performance was better than that obtained with the same methodology applied on the strain curves, reading of two expert cardiologists as well as comparative classification systems using only the spatial distribution of the end-systolic strain and peak-systolic strain rate values. This study shows the potential of machine learning in the field of cardiac deformation imaging where an efficient representation of the spatio-temporal characteristics of the segmental deformation curves allowed automatic classification of infarcted from control hearts with high accuracy.

Multi-transmit beam forming for fast cardiac imaging--experimental validation and in vivo application.

High frame rate (HFR) echocardiography may be of benefit for functional analysis of the heart. In current clinical equipment, HFR is obtained using multi-line acquisition (MLA) which typically requires broadening of transmit beams. As this may result in a significant degradation of spatial resolution and signal-to-noise ratio (SNR), the capacity of MLA to obtain high quality HFR images remains limited. As an alternative, we have demonstrated by computer simulation that simultaneously transmitting multiple focused beams into different directions [multi-line transmit (MLT)], can increase the frame rate without significantly compromising the spatial resolution or SNR. This study aimed to experimentally verify these theoretical predictions both in vitro and in vivo to demonstrate, for the first time, that cardiac MLT imaging is feasible. Hereto, the ultrasound advanced open platform, equipped with a 2.0 MHz phased array, was programmed to interleave MLT and conventional single line transmit (SLT) beam forming. Using these two beam forming methods, images of phantoms and healthy volunteers were acquired and investigated both qualitatively and quantitatively. The results confirmed our simulations that image quality of a 4MLT imaging system with a Tukey apodization scheme is very competitive to that of SLT while providing a 4 times higher frame rate. It is also demonstrated that MLT can be combined with MLA to provide images at 12- to 16-fold frame rate (about 340-450 Hz) without significantly compromising spatial resolution and SNR. This is thus the first study to demonstrate that this new ultrasound imaging paradigm is viable which could have significant impact on future cardiac ultrasound systems.

Incremental value of the en face view of the tricuspid valve by two-dimensional and three-dimensional echocardiography for accurate identification of tricuspid valve leaflets.

BACKGROUND: In this study, advanced postprocessing of three-dimensional echocardiographic (3DE) data sets was used to identify tricuspid valve (TV) leaflets in two-dimensional echocardiographic (2DE) views, and the feasibility of the subcostal view to obtain 2DE en face views of the TV, as an alternative imaging option to image reconstruction from 3DE imaging, was also tested. METHODS: In 155 consecutive patients, attempts were made to obtain the en face view of the TV by 2DE imaging (from the subcostal window) and by reconstruction from 3DE imaging. Using both in-house-developed and commercially available software for postprocessing of 3DE data, image planes from the standard 2DE views were reconstructed and TV leaflets identified in each view. RESULTS: With 2DE imaging, all TV leaflets could be visualized in 58% of patients, compared with 56% using 3DE imaging. In 30 patients (19%), en face views of the TV could be obtained only by 3DE imaging. The anterior leaflet was the largest one in 90% of patients, and the smallest leaflet was either the posterior (49%) or septal (41%) leaflet. In 12% of patients, the TV was either bicuspid or quadricuspid. In patients with pacemakers, the position of the right ventricular lead relative to the TV leaflets was readily determined using both imaging techniques. Visible TV leaflets varied in all standard 2DE views because of variability in image planes and leaflet morphology. CONCLUSIONS: High variability in TV leaflet anatomy and the dependence on transducer position do not allow schematic leaflet identification. All existing TV leaflet identification schemes are therefore only partially correct, and if correct leaflet identification is needed, the use of an en face view is recommended.

Consistent regional heterogeneity of passive diastolic stretch and systolic deformation in the healthy heart: age-related changes in left ventricle contractility.

The consistency of the normal spatial distribution of segmental passive stretch (PreS) and systolic strain (SS) within the left ventricle was investigated and a recently proposed echocardiographic estimate of left ventricular (LV) contractility was used to detect contractility changes with age. Hereto, in 54 healthy subjects, segmental PreS and SS were measured on tissue Doppler images of six left ventricle walls. For each subject, a linear regression line was estimated through the segmental PreS and SS values. The slopes and intercepts of this PreS-SS relationship did not differ between age groups, suggesting no changes in LV contractility with age. Moreover, a consistent regional distribution of PreS was observed, with the highest values measured in the septum, resulting in a similar distribution of SS as a direct consequence of the Frank-Starling mechanism.

Elastic image registration to quantify 3-D regional myocardial deformation from volumetric ultrasound: experimental validation in an animal model.

Although real-time 3-D echocardiography has the potential to allow more accurate assessment of global and regional ventricular dynamics compared with more traditional 2-D ultrasound examinations, it still requires rigorous testing and validation should it break through as a standard examination in routine clinical practice. However, only a limited number of studies have validated 3-D strain algorithms in an in vivo experimental setting. The aim of the present study, therefore, was to validate a registration-based strain estimation methodology in an animal model. Volumetric images were acquired in 14 open-chest sheep instrumented with ultrasonic microcrystals. Radial strain (ɛRR), longitudinal strain (ɛLL) and circumferential strain (ɛCC) were estimated during different stages: at rest, during reduced and increased cardiac inotropy induced by esmolol and dobutamine infusion, respectively, and during acute ischemia. Agreement between image-based and microcrystal-based strain estimates was evaluated by their linear correlation, indicating that all strain components could be estimated with acceptable accuracy (r = 0.69 for ɛRR, r = 0.64 for ɛLL and r = 0.62 for ɛCC). These findings are comparable to the performance of the current state-of-the-art commercial 3-D speckle tracking methods. Furthermore, shape of the strain curves, timing of peak values and location of dysfunctional regions were identified well. Whether 3-D elastic registration performs better than 3-D block matching-based methodologies still remains to be proven.

The slope of the segmental stretch-strain relationship as a noninvasive index of LV inotropy.

OBJECTIVES: The aim of this study was to test the hypothesis that the noninvasively constructed slope of the relationship between left ventricular (LV) regional systolic strain and stretch during atrial contraction represents LV inotropic state. BACKGROUND: LV systolic response to a changing preload depends on its inotropic state. Changing the preload has allowed constructing the slope of the end-systolic pressure-volume relationship that is used as an invasive measurement of LV inotropy. We assumed that the slope of the relationship between regional systolic LV strain (total_S) and stretch during atrial contraction (preS) depends on the LV inotropic state as well and can thus be used as a LV inotropy index. METHODS: Strain curves (tissue Doppler) were extracted from 27 healthy individuals to determine the normal stretch-strain relationship at rest, during a low-dose dobutamine (LD) challenge and during passive leg-lift (LL). The method was also applied in 7 patients with breast cancer before and after chemotherapy with anthracyclines. RESULTS: PreS and total_S correlated closely in all subjects (r = 0.82). Total_S values increased (p < 0.05) with LD (-20.44 ± 3.89% vs. -24.24 ± 5.55%) and LL (-19.65 ± 3.77% vs. -24.05 ± 3.67%), whereas preS increased only with LL (5.96 ± 1.72% vs. 8.61 ± 2.18%), but not with LD (6.83 ± 2.34% vs. 7.29 ± 2.24%). No changes of total_S or preS were observed after the exposure to chemotherapy (-21.23 ± 2.93% vs. -21.49 ± 2.89% and 8.11 ± 1.03% vs. 8.59 ± 1.73%, respectively). The slope of stretch-strain relationship got steeper with LD (-1.47 ± 0.36 vs. -2.34 ± 0.36, p < 0.05), declined after the chemotherapy (-1.68 ± 0.15 to -0.86 ± 0.23, p < 0.05) and did not change with LL (-1.39 ± 0.57 vs. -1.51 ± 0.38, p = NS). CONCLUSIONS: The slope of the regional stretch-strain relationship can be regarded as a noninvasive index of myocardial inotropic state. It gets steeper with increasing inotropy, does not change with preload induced changes of LV systolic function, and flattens after the exposure to a cardiotoxic drug.

Elastic image registration versus speckle tracking for 2-D myocardial motion estimation: a direct comparison in vivo.

Despite the availability of multiple solutions for assessing myocardial strain by ultrasound, little is currently known about the relative performance of the different methods. In this study, we sought to contrast two strain estimation techniques directly (speckle tracking and elastic registration) in an in vivo setting by comparing both to a gold standard reference measurement. In five open-chest sheep instrumented with ultrasonic microcrystals, 2-D images were acquired with a GE Vivid7 ultrasound system. Radial (ε(RR)), longitudinal (ε(LL)), and circumferential strain (ε(CC)) were estimated during four inotropic stages: at rest, during esmolol and dobutamine infusion, and during acute ischemia. The correlation of the end-systolic strain values of a well-validated speckle tracking approach and an elastic registration method against sonomicrometry were comparable for ε(LL) ( r=0.70 versus r=0.61, respectively; p=0.32) and ε(CC) ( r=0.73 versus r=0.80 respectively; p=0.31). However, the elastic registration method performed considerably better for ε(RR) ( r=0.64 versus r=0.85 respectively; p=0.09). Moreover, the bias and limits of agreement with respect to the reference strain estimates were statistically significantly smaller in this direction . This could be related to regularization which is imposed during the motion estimation process as opposed to an a posteriori regularization step in the speckle tracking method. Whether one method outperforms the other in detecting dysfunctional regions remains the topic of future research.

Current state of three-dimensional myocardial strain estimation using echocardiography.

With the developments in ultrasound transducer technology and both hardware and software computing, real-time volumetric imaging has become widely available, accompanied by various methods of assessing three-dimensional (3D) myocardial strain, often referred to as 3D speckle-tracking echocardiographic methods. Indeed, these methods should provide cardiologists with a better view of regional myocardial mechanics, which might be important for diagnosis, prognosis, and therapy. However, currently available 3D speckle-tracking echocardiographic methods are based on different algorithms, which introduce substantial differences between them and make them not interchangeable with each other. Therefore, it is critical that each 3D speckle-tracking echocardiographic method is validated individually before being introduced into clinical practice. In this review, the authors discuss differences and similarities of the currently available 3D strain estimation approaches and provide an overview of the current status of their validation.

The heart in Friedreich ataxia: definition of cardiomyopathy, disease severity, and correlation with neurological symptoms.

BACKGROUND: This cross-sectional study provides a practical approach for the clinical assessment of Friedreich ataxia (FA) cardiomyopathy (FA-CM). METHODS AND RESULTS: A comprehensive cardiac assessment, including standard echocardiography, color Doppler myocardial imaging, cardiac magnetic resonance imaging, ECG, and exercise stress testing, was performed in 205 FA patients. To assess myocardial hypertrophy in FA-CM, the end-diastolic interventricular septal wall thickness (IVSTd) was found to be the best echocardiographic parameter compared with cardiac magnetic resonance imaging-determined left ventricular mass. With the use of this parameter, 4 groups of patients with FA-CM could be defined. Patients with normal values for IVSTd (31.7%) were classified as having no FA-CM. Patients with an IVSTd exceeding the predicted normal IVSTd were classified as having mild FA-CM (40%) if IVSTd exceeded the normal value by <18% or as having intermediate FA-CM (16.1%) if IVSTd exceeded the normal value by ≥18%. Patients with ejection fraction <50% were classified as having severe FA-CM (12.2%). In addition to increased myocardial mass, severe FA-CM was further characterized by dilatation of the left ventricle, reduced systolic strain rate of the posterior wall, and ECG abnormalities. Regional myocardial function correlated negatively with FA-CM groups. Younger patients had a tendency for more advanced FA-CM. Importantly, no clear correlation was found between FA-CM groups and neurological function. CONCLUSIONS: We provide and describe a readily applicable clinical grouping of the cardiomyopathy associated with FA based on echocardiographic IVSTd and ejection fraction data. Because no distinct interrelations between FA-CM and neurological status could be determined, regular follow-up of potential cardiac involvement in FA patients is essential in clinical practice.

Comparison of a new methodology for the assessment of 3D myocardial strain from volumetric ultrasound with 2D speckle tracking.

An alternative approach to extract 3D myocardial strain based on elastic registration of the ultrasound images (3DSE) was developed by our lab. The aim of the present study was to test its clinical performance by comparing strain values obtained by 3DSE with the ones obtained with 2D speckle tracking (2DST). Standard 2D B-mode and volumetric datasets were acquired in 12 patients with coronary heart disease (CHD) and in 12 control subjects. Longitudinal (ε(LL)), circumferential (ε(CC)) and radial (ε(RR)) strain values were obtained from 2D datasets using commercially available 2DST software and from volumetric datasets using the 3DSE approach. 3DSE provided lower strain values than 2DST. With both approaches global ε(LL) and ε(CC) were significantly lower in patients with CHD than in controls. Global ε(LL) and ε(CC) correlated well between both methods (R = 0.83, R = 0.86, respectively), while segmental correlations were moderate [R = 0.63 (ε(LL)), R = 0.41 (ε(CC))]. The highest differences in ε(LL) values obtained by the two methods and the highest number of erroneous ε(LL) with 3DSE were observed in the basal LV segments. This study shows that in real-life datasets our 3DSE method provides global and regional ε(LL) and ε(CC) values that are comparable with the ones obtained from 2DST, even though they are not interchangeable with each other. As only a single acquisition is required, 3D methods may offer advantages over the current 2D techniques. However, the accuracy of the 3DSE can still be improved by solving the problems that appear with deformation estimation in the basal segments.